The invention relates generally to implementation of services in a telecommunications network, particularly an intelligent network. The service may be any service produced in the network for a network user or another object.
The rapid evolvement of the telecommunications field has afforded operators the capability of providing many different types of services to users. A network architecture that provides advanced services is called an intelligent network. The common abbreviation for intelligent network is IN.
The functional architecture of an intelligent network is shown in FIG. 1 where the functional entities of the network are shown as ovals. This architecture is described briefly below, because the invention will be described hereinafter with reference to the intelligent network environment.
The access of the end user,(subscriber) to the network is handled by the CCAF (Call Control Agent Function). The access to the IN services is implemented by making additions to existing digital exchanges. This is done by using the basic call state model BCSM which describes the existing functionality used to process a call between two users. The BCSM is a high level state automaton description of the call control functions CCF required for establishing and maintaining a connection route between users. Functionality is added to this state model by using the service switching function SSF (cf. the partial overlap of the entities CCF and SSF in FIG. 1) so that it is possible to decide when it is necessary to call the services of the intelligent network (the IN services). After these IN services have been called, the service control function SCF that contains the service logic for the intelligent network handles the service-related processing (of the call attempt). The service switching function SSF thereby connects the call control function CCF to the service control function SCF and allows the service control function SCF to control the call control function CCF. For example, SCF can request that the SSF/CCF perform specific call or connection functions, for example charging or routing operations. The SCF can also send requests to the service data function SDF which handles the access to the service-related data and network data of the intelligent network. The SCF can thus for example request the SDF to retrieve specific service-related data or update this data.
The functions described above are further complemented by the specialized resources function SRF which provides the special functions required for implementing some of the services provided by the intelligent network. Examples of these services are protocol conversions, speech recognition, voice mail, etc. The SCF can, for example, request the SSF/CCF functions to first establish a connection between the end users and SRF and then it can request the SRF to give voice announcements to the end users.
Other functional entities of the intelligent network are various functions that relate to control, such as the SCEF (Service Creation Environment Function), SMF (Service Management Function), and SMAF (Service Management Access Function). The SMF includes, among other things, service control, the SMAF provides the connection to the SMF, and the SCEF makes it possible to specify, develop, test and feed IN services via the SMF to the SCF. Because these functions only relate to the operation of the network operator, they are not shown in FIG. 1.
The role of the functional entities described in FIG. 1 as relating to the IN services will be briefly described below. The CCAF receives the service request given by the calling party. The service request usually consists of lifting the receiver and/or a series of digits dialled by the calling party. The CCAF further transmits the service request to the CCF/SSF for processing. The call control function CCF does not have the service data but it has been programmed to recognize the need of a service request. The CCF interrupts the call setup for a moment and notifies the service switching function SSF about the state of the call. The task of the SSF is, using predefined criteria, to interpret the service request and thus determine whether the request is a service request related to the IN services. If this is the case, the SSF composes a standardized IN service request and sends the request to the SCF along with information about the state of the service request. The SCF receives the request and decodes it. After that it cooperates with the SSF/CCF, SRF, and SDF to provide the requested service to the end user.
The physical level architecture of the intelligent network describes how the functional entities described above are located in the physical entities of the network. The physical architecture of the intelligent network is illustrated in FIG. 2, where the physical entities are described as rectangles or circles and functional entities as ovals. The signalling connections are described by dashed lines and the actual transport which is for example speech, by continuous lines. The optional functional entities are denoted with dashed line.
The signalling network shown in the Figure is a network according to SS7 (Signalling System Number 7 is a well-known signalling system described in the CCITT (nowadays ITU-T) blue book Specifications of Signalling System No. 7, Melbourne 1988).
The subscriber equipment SE which can include, for example, a telephone, computer, or telefax, are connected either directly to a service switching point SSP or to a network access point NAP.
The service switching point SSP provides the user with access to the network and handles all necessary selection functions. The SSP can also detect any IN service requests. Functionally, the SSP includes the call control and service selection functions.
The network access point NAP is a traditional telephone exchange that includes the call control function CCF, for example, the Applicants"" DX 220 exchange which can differentiate calls that require IN services from traditional calls and route the calls that require IN services to the appropriate SSP.
The service control point SCP includes the service logic programs SLP that are used to produce the IN services. The shorter term service program will also be used for service logic programs in the following.
The service data point SDP is a database containing customer and network data which is used by the service programs of the SCP to produce tailored services. The SCP can use SDP services directly via the signalling or data network.
The intelligent peripheral IP provides special services, such as announcements and voice and multiple choice recognition.
The service switching and control point SSCP consists of an SCP and SSP located in the same network element (in other words, if the SSP network element shown in the drawing contains both an SCF and an SSF entity, the network element in question is an SSCP).
The tasks of a service management system SMP include the management of the database (SDP), network monitoring and testing, and collecting network data. It can connect to all other physical entities.
The service creation environment point SCEP is used for specifying, developing and testing the IN services, and for entering the services in SMP.
The service adjunct AD is functionally equivalent to the service control point SCP, but it is directly connected to SSP with a fast data connection (for example, with an ISDN 30B+D connection) instead of via the common channel signalling network SS7.
The service node SN can control the IN services and perform data transfers with users. It communicates directly with one or more SSPs.
The service management access point SMAP is a physical entity which provides certain users with a connection to SMP.
The above is a brief description of the intelligent network as a background to the description of the method according to the invention. The interested reader can get a more detailed description of the intelligent network in, for example, ITU-T specifications Q.121X or in the AIN specifications of Bellcore.
It should be possible to provide IN-based services to subscribers in fixed or mobile networks in a way enabling provision of individual service tailored to personal needs as far as possible. As stated previously, provisioning of a service is in practice initiated in such a way that the SSF sends to the SCF a standard IN service request. The service request can be sent at certain stages of the call setup. The international standards, however, specify only one identifier for the service request sent by the SSF wherewith the desired service logic can be selected in the SCP. This identifier is called the service key.
The generally known technique for providing tailored services is such that the final service logic program (SLP) is selected in the SCP by means of the service key value, in which case more than one values can point to the same service logic program or there may be a dedicated service logic program for each service key value.
This solution means that the service key values used in the SSP exchange must be used in the SCP exchange to select the service logic programs, even though the key is originally intended merely for identifying the service. The drawback with this solution is that the implementation of the network will be rendered far more difficult with the increase in services and features contained in them, as one strives at providing subscribers (or other objects) with services better tailored than heretofore to specific personal needs. In the future, an individual IN service may comprise for example 10 different service features, in which situation each subscriber can select a service suited to him, consisting of a desired subset of said features or a combination of all features. A subservice, for which the English term service feature (SF) is employed in the international standards, will be termed a feature in this context.
Hence, the problem must be solved how it is possible to indicate using the standard service key mechanism the specific subset of service features relating to an individual object, e.g. an individual subscriber, simultaneously keeping the network implementation and maintenance as simple as possible.
It is an object of the invention to provide a solution to the above-described problem.
This object is achieved with the solution in accordance with the invention, which is defined in the independent claims.
The idea of the invention is to define for an individual service key value the set of features that are allowable, and first to select said set by means of the service key arriving in each case and thereafter to search object-specifically which features relating to said object and indicated as active belong to said set. Thereafter the service can be provided by executing the features found, or at least some of them.
By means of solution in accordance with the invention, a system can conveniently be achieved in which the set of features to be executed changes according to which service key value and which object are concemed. This affords more flexibility in producing the services, and enlarging the service selection available to subscribers will be simplified.
The solution in accordance with the invention also affords an advantageous solution in view of network management, since the SSP exchange can utilize a small number of different values as service keys on account of the fact that the SSP exchange only has to identify those subscribers who have a version of a given IN service or of a service belonging to a group of related IN services. In that situation, on the basis of said service key a process is selected in the SCP exchange that is capable of finding, by examining a subscriber-specific information element, what kind of service version said subscriber has.